Having had the dubious pleasure of having not one, but more like twenty one people decide to clamber into my aircraft, through every opening possible, I can vouch that getting airborne is the best option if possible. In my case, it was not possible to do so safely and I was then left with the safety of everyone around the aircraft literally in my hands. Firstly as the co-pilot was dragged out, smacking the cyclic as he went, then with a bunch of various individuals climbing through my window, across the centre pedestal and over my back, who were more concerned with restraining my arms as they thought I would try and escape!
The prospect of the cyclic being exercised through it's full range, whilst running, and a bunch of people fighting under the disc did not fill me with delight
Luckily I was able to free my arm long enough to pull the T-Handles and turn off the battery, then back to the controls for the run down - which being unable to use the rotor brake took an age!
At least I got a free holiday out of it.......
So, I would say that getting airborne - if safely possible - is by far the best option. People grabbing you whilst at the controls is no fun.